Final answer:
The nurse practitioner should order serum B12 and folate for this patient. The patient's symptoms and physical findings are suggestive of megaloblastic anemia, which can be caused by a deficiency in vitamin B12 and/or folate.
Step-by-step explanation:
The nurse practitioner should order serum B12 and folate for this patient. The patient's symptoms, including numbness and tingling in the hands, fatigue, and difficulty walking, along with the physical findings of pallor, pale conjunctiva, glossitis, and weak hand grip, are suggestive of megaloblastic anemia. Megaloblastic anemia is commonly caused by a deficiency in vitamin B12 and/or folate. By ordering serum B12 and folate levels, the nurse practitioner can determine if a deficiency in one or both of these nutrients is responsible for the patient's symptoms.